1. Field of the Invention
The present invention relates to a method of manufacturing an inflator of a hybrid type or a stored type having a construction in which a pressurized gas for supplying to an air bag as an inflation gas is filled.
2. Related Art
Conventionally, in an inflator of a type which is constructed by filling a pressurized gas into the interior of a housing (also called a bottle), an opening for filling the pressurized gas is formed in the housing. After the filling of the pressurized gas, this opening is blocked by a blocking body (also called a welding pin) which is welded to the peripheral edge of the opening by resistance-welding (e.g., refer to JP-A-2000-227199).
In the manufacture of such an inflator, the peripheral edge of the opening of the housing is covered with a cylindrical cover while ensuring sealability (gastightness), and the blocking body is disposed in the opening so as to be inserted into the opening with a gap provided between the blocking body and the inner peripheral surface of the opening. Further, an electrode for resistance-welding is disposed above the blocking body. Subsequently, the pressurized gas which is supplied from a pressurized gas source is caused to flow into the cover, and the pressurized gas which flowed in is filled in the housing through the gap between the blocking body and the inner peripheral surface of the opening. Upon completion of the filling of the pressurized gas into the housing, in the state in which the cover is pressed against the peripheral edge of the opening to ensure gastightness, the electrode is lowered so as to press the blocking body. While the blocking body is being pressed against the peripheral edge of the opening, the blocking body is energized with a resistance-welding current to thereby resistance-weld the blocking body to peripheral edge of the opening and fix the blocking body so as to block the opening, thereby manufacturing the inflator.
However, with the conventional method of manufacturing an inflator, the blocking body is not fixed to the peripheral edge of the opening in the atmospheric environment. Namely, under the pressure (35 to 55 MPa) of the pressurized gas being filled into the housing, the blocking body is resistance-welded while ensuring gastightness by the cover for the surroundings of the opening, the blocking body, and the electrode for resistance-welding so that gas leakage is absent. For this reason, a filling device which is equipped with a filling nozzle and the electrode becomes complex including the sealing structure of a movable portion of the electrode in the cover. Hence, there has been leeway for improvement in the manufacture of the inflator in a simple manner.